Recordings of ore falls in mines

Recordings of ore falls in Khibiny mines have typical features which enable an experienced analyst to recognize them easily:

weak of absent P and S recordings;

strong Rayleigh waves;

apparent velocity of Rayleigh waves by AP0 array is within the limits 2.5 - 3.5 km/sec;

Typical example of ore falls recordings in Khibiny. Apatity array recording is on top, Apatity broadband station bottom. Low-frequency surface waves are prevailing. A backazimuth was computed by surface waves (points to Yukspor mine) and apparent velocity of the waves appeared 3.3 km/sec.